Cruise control systems for maintaining a desired vehicle speed have been available heretofore, and their benefits are well known. One benefit is to reduce operator or driver fatigue. Such systems are often found on automobiles. In automotive applications, cruise control systems are generally interconnected with the brake pedal and can be disengaged either by turning them off or tapping the brake pedal to actuate a cut-out switch. However, some vehicles such as commercial riding mowers utilize hydrostatic drive systems with dynamic braking characteristics. Such vehicles typically have a traction pedal which is connected through a linkage to a lever on the pump in order to control the direction and speed of flow through the motors in the hydraulic circuit. Individually controlled brakes are sometimes provided for steering assist. However, brake systems are typically not provided in this type of vehicle, except perhaps for a parking brake.
Speed controls for riding mowers and other hydrostatically driven vehicles have also been available heretofore. For example, U.S. Pat. No. 4,620,575 to Cuba, et al shows a speed control for a lawn and garden vehicle. U.S. Pat. No. 4,553,626 to Kazmierczak, et al, U.S. Pat. No. 4,281,737 to Molzahn, and U.S. Pat. No. 4,727,710 to Kuhn are representative of the prior art in this regard. These systems tend to be relatively complicated and are also interconnected with the brake pedals. The Toro system incorporating electromagnets responsive to a switch associated with the brake pedal on a riding mower. However, there has not been available heretofore a cruise control system for vehicles having hydrostatic drives with traction pedals but no brake pedals.
There is thus a need for an improved cruise control system which is adapted for use on a hydrostatically driven vehicle having only a traction pedal but no brake pedal.